[请教]BIOS地址映射?

暴雪

原512K的ROM，现换了一个1M的ROM，windows下在 0xFFF0 0000~0xFFF7 FFFF 可以看到追加的512K的内容。
4 D* o; f$ P6 D: R. J但在启动计算机时(BIOS没有初始化计算机），无法访问追加的512K的ROM。
& E$ M- x  x' W5 w  w(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)

1 @! G/ U  f) U3 p  ~我的计算机用的是intel的ICH7南桥。
在手册上
FWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
7 B$ J' g. x8 Z+ H9 i5 m( \# QFWH_70_IDSEL — R/W. IDSEL for two, 1-M Firmware Hub memory ranges.
" `5 p5 {) |$ [8 ^. a6 |The IDSEL programmed in this field addresses the following memory ranges:
/ |  D. }, J0 BFF70 0000h – FF7F FFFFh
3 F" q1 ~, |  o. M% yFF30 0000h – FF3F FFFFh
* I  h' p5 x9 y) n在这里 IDSEL 如何理解。
FWH_DEC_EN1—Firmware Hub Decode Enable Register
5 \# C8 U2 A2 f8 ?  ~# J(LPC I/F—D31:F0)
FWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
' l5 N- j; q" l) T# V' ~0 = Disable.
1 = Enable the following ranges for the Firmware Hub
$ c1 m' h/ c4 V! W) NFF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
4 n% `2 M& ]) k* S1 W6 v8 p除了上面的数据区域，还有其它的数据区域控制ROM到内存地址的映射吗？
3 [/ D( b- Y8 `  }; r3 S1 U
$ M, q! @! j$ R, w  _谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
This one clock field is used to indicate which of multiple Firmware components is being selected.
5 g$ @0 G7 X2 C+ P8 m6 ?The four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
' t5 X; X1 `: B: Ppins on the Firmware component. If there is a match, the Firmware component will continue to
decode the cycle to determine which bytes are requested on a read or which bytes to update on a
& z- X' d- M) u2 U. f. x( xwrite. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
a standby power state.
% |8 N$ X" \" O6 L& B  H% \! {4 X
详见LPC spec:
http://www.intel.com/design/chipsets/industry/25128901.pdf

9 M* s$ H' f% R" z$ h- u在ICH 7 中似乎就这几个吧(FWH_SEL1,FWH_SEL2,FWH_DEC_EN1,BIOS_CNTL),据我现在知道的.